Abgleich / Alignment
UMS 1 / UMS 2
2 - 6
GRUNDIG Service
Alignment
1. Tuner
Test Equipment:
Sweep generator, Test generator, Stereo coder, AF generator, Oscilloscope, Digital voltmeter, AF voltmeter, Distortion meter
Note:
The frontend is a completely preadjusted module. Only the IF filter must be adjusted to the IF amplifier (1). The values of the tuning voltages are:
87.5MHz = typ. 1.6V min 1.3V
108MHz = typ. 8.0V max 9V
ķ
Adjustment
Preparations
Adjustment Procedure
1. IF Filter
2. Demodulator
3. Station search
4. Stereo Crosstalk
5. Adjacent channel
filter
6. 38 kHz Filter
7. 19 kHz Filter
8. MW Oscillator
9. MW RF Circuits
FM, 98MHz.
Sweep generator 98MHz to aerial socket. Level approx.
100
µ
V / 75
Ω
.
Oscilloscope to testpoint B .
FM, 98MHz
Test generator 98MHz to aerial socket. Level approx.
100
µ
V / 75
Ω
,
∆
f =
±
40kHz.
Distortion meter to AF output .
FM, 98MHz.
Test generator 98MHz, V
RF
= 100
µ
V / 75
Ω
to aerial socket.
Digitalvoltmeter to testpoint
G
.
FM
Stereocoder, left channel modulated, to aerial socket.
AF voltmeter to AF output, right channel .
FM
AF generator 114kHz, approx. 100mV to the input of F2
D
(Pin 2).
AF voltmeter to the output of F2
D
D
D
D
D
(Pin 4).
FM
Test generator to aerial socket; FM, f
mod
= 38kHz.
AF voltmeter to AF output .
Test generator to aerial socket; FM, f
mod
= 19kHz.
AF voltmeter to AF output .
MW, 531kHz
Digitalvoltmeter to testpoint
E
.
MW, 1449kHz / 558kHz
Test generator via 120 -150
µ
H parallel to frame aerial; AM,
V
RF
= 3
µ
V, m = 30%, f
mod
= 1kHz.
AF voltmeter to AF output .
Adjust
F1
a
to
maximum and symmetry.
Adjust
F7
i
to
K
min
(typ. 0.12%, max. 0.2%).
Adjust
R123
S
to
1.2V + 0.05V.
Adjust
R69
C
to minimum.
Control the left AF output with modulated right channel.
Adjust
F2
D
to
minimum
.
Adjust
F9
J
(left channel) and
F11
K
(right channel) to
minimum
.
Adjust
F9
G
(left channel) and
F11
H
(right channel) to
minimum
.
Adjust
L18
VI
to
1.1V.
Adjust
C3
IV
and IF filter
F6
VII
at 1449kHz and
L1
III
at 558kHz to
maximum
. Repeat the adjustment
reciprocally
C3
and
L1
, end with 1449kHz.
L
R
R
L
R
L
R
L
R